Is there a way to pause and resume query output?

I’m using the eventEmitter model to handle the results from a query that produces a large number of rows. The handler has some async components, so I’d really like to be able to keep the next ‘row’ event from firing until after the current one has completed processing.

Ideally this would take to form of pause() and resume() calls on the query object itself.

 var query = client.query("select * from big_data_table");
 query.on('row', function (row) {
    query.pause(); // turn off the firehose
    return do_something_async(row, function() {
      query.resume(); // turn back on the firehose
    });
 });

[TeddyPerkins77]

@brianc thank you for quick response! I ended up using query-stream.

@jgoux this worked for me buddy:

var QueryStream = require('pg-query-stream')
var pg = require('pg')

var conString = "yourConnectionString";
var client = new pg.Client(conString);

client.connect(function(err) {
       if(err) {
             return console.error('could not connect to postgres', err);
        }

    if(err) throw err;
    var query = new QueryStream(queryStr, values)
    var stream = client.query(query)

    stream.on('data', function(row) {
        stream.pause();
            //handle your async process here
        stream.resume();
    })
    stream.on('end', function() {
        client.end();
    })
});

Cheers!

[jgoux]

I’m interested as well. I’d like to handle an async process inside the data handler, and receive the next row only when my async process in the handler is over.